Plasmids pSP1 and pSP2 are two new Schizosaccharomyces pombe ars1 multicopy vectors with the Saccharomyces cerevisiae LEU2 and URA3 genes as selectable markers. They are derivatives of S. cerevisiae integrative plasmids. These plasmids allow classical molecular genetic techniques, such as mutagenesis, nested deletions and sequencing, to be performed directly.